The present invention relates to a method for achieving an optimal energy exchange in regenerative heat exchange between the combustion air and precooled, wet flue gases from a cooling device.
When flue gases containing water vapour are cooled down to temperatures under their dew point, the water vapour can condense and the condensation heat be recovered. A further drop in temperature is possible by a regenerative heat exchange between the combustion air and the precooled, wet flue gases, further water vapour being condensed on the fume side and being vaporized on the combustion air side. As the combustion air simultaneously with being heated is wetted, an essential part of the energy can be transferred from the flue gases to the combustion air. The transferable energy amount, however, is limited by the fume side condensation being achieved during the regenerative heat exchange which does not sufficiently correspond to the combustion air side vaporization capability.
The invention has as an object in a simple way to achieve an optimal energy exchange for the method mentioned above.